Stereo-structures of reaction products of thymidine epoxides with amines and L-amino acid ethyl esters

Abstract

Reaction of thymidine epoxide (6) derived from (5R,6R)-trans-(+)-5-bromo-6-hydroxy-5,6-dihydrothymidine (2) with amines and L-amino acid ethyl esters afforded cis adduct (10) and that of the epoxide (8) derived from (5S,6S)-trans-(–)-5-bromo-6-hydroxy-5,6-dihydrothymidine (4)cis and trans adducts (12) and (14). The stereo-structures of the products were elucidated on the basis of isomerisation of the trans adducts to the cis adducts by using boron trifluoride–diethyl ether, X-ray analyses of (10a) and (10d), and the specific rotations of the compounds.